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Multiple-Input Buck Boost Power Converter A power converter circuit to convert multiple direct current (dc) inputs to one or more dc outputs. This dc-dc power converter allows its load to be powered by multiple,... Read More A power converter circuit to convert multiple direct current (dc) inputs to one or more dc outputs. This dc-dc power converter allows its load to be powered by multiple, different sources of various voltage and current levels (such as solar panels, batteries, fuel cells, etc.). This converter has both buck and boost capability. This circuit can simultaneously draw power from several dc electrical energy sources of different kinds (such as solar panels, batteries, fuel cells, etc.). The circuit topology is capable of an arbitrary number of input sources of different voltage/current/power levels. There is a single output voltage that can directly supply a load, or can supply another power converter. The default circuit uses an inductor, but it may be substituted with a transformer to provide electrical isolation or multiple output as well. The power flow from each source can be controlled separately in order to optimize the power flow characteristics for cost, environmental protection, or any other performance objective. Low power applications regulate source switching with a control circuit. High power applications regulate and optimize flow characteristics with a digital signal processor (DSP). This circuit contains a minimum number of components which reduce overall complexity and cost when compared to other implementations. In addition, due to efficiency in design, this circuit can be scaled to work across a multitude of power ranges. Applications: This technology can be used in any application which uses multiple dc energy sources and in situations where backup or simultaneous alternative energy sources are used. Such sources include solar cells, fuel cells, batteries, and thermoelectric sources. Benefits: Simple: Designed with minimal parts, allowing for reduced complexity in design and higher reliability. Low Cost: Requires fewer inductors and transistors when compared to equivalent dc-dc converters, therefore manufacturing costs are reduced. Efficient: Less loss and higher conversion efficiency due to the minimal design parts. Adaptable: Easily integrated into existing systems and combined with other converters (i.e. ac-dc). To license the entire Solar Panels portfolio, click here.
Transpiration Cooling for Structural Polymer Materials Researchers from the Beckman institute at the University of Illinois are developing a system for cooling structural materials inspired on nature's transpiration.... Read More Researchers from the Beckman institute at the University of Illinois are developing a system for cooling structural materials inspired on nature's transpiration. Using porous materials and leveraging capillary forces, Scott White's lab created a transpiration system to cool down a surface. The system is autonomous, self powered, and inexpensive. In addition, the principle of transpiration make this cooling solution self regulated requiring minimum user input after the system is installed. The new system will enable the use of polymer materials for applications where high temperatures would degrade non-cooled polymers.
One-Part Liquid Composite Molding Technique This technique for liquid composite molding uses a solid catalyst recrystallized onto preplaced fiber reinforcements to produce high-strength polymer matrix... Read More This technique for liquid composite molding uses a solid catalyst recrystallized onto preplaced fiber reinforcements to produce high-strength polymer matrix composites. The polymerization is initiated by the preform itself, eliminating the need to mix multiple resins and catalysts before filling the mold. Having polymerization triggered by the preform simplifies the process, saves time, and eliminates mixing equipment. Liquid composite molding processes have been popular since the 1940s. In the last 10 to 15 years, significant improvements have been made in developing low-viscosity thermosetting resin systems necessary to obtain high fiber volume parts. Also, automatic methods like weaving, braiding, and knitting have greatly reduced the cost of producing fiber preforms. All liquid composite molding processes require that the resin injected into the mold is a reactive liquid. Some resins such as epoxy and urethane are highly reactive and must be kept separate until just before they are injected into the mold. Other resins are activated by a catalyst in the holding tank. These multipart resin systems require complex mixing, metering, and use of injection equipment with accurate ratio control. The multipart resin systems also may require heating tanks, hoses, pipes, and pumps; motionless mixing; efficient circulation to help prevent cure or degradation of the resin in a holding tank; and easy and safe cleaning/purging. This new liquid composite molding technique uses a one-part monomer and a solid catalyst crystallized onto the fiber reinforcement. The polymerization is initiated by the preform itself, eliminating the need to mix or add multiple resins and catalysts before filling the mold. Since it uses a single resin, the process also eliminates the need for the mixing equipment and reduces the heating and cleaning requirements of the injection equipment. The best material system for use with this technology is one that uses polydicyclopentadiene (pDCPD). This polymer forms very rapidly at room temperature by a ring-opening metathesis polymerization (ROMP) of its low-viscosity monomer. The first step in this process requires recrystallizing the catalyst onto the fiber preform. The reactive fiber preform is then placed into the mold, the mold is closed, and the monomer is injected into it. Once the monomer has had time to react with the catalyst on the fiber preform and polymerize, the completed part is removed from the mold. Applications This technique can be used in liquid composite molding, such as resin transfer molding (RTM), vacuum-assisted RTM (VARTM), and structural reaction injection molding (SRIM), for parts with end-use applications in: Aerospace Sports Recreation Marine and Automotive Equipment Ballistics Electronics Benefits Because multiple resins and catalysts do not need to be added or mixed before being pumped into the mold, this process: Simplifies production: This technique provides a simpler process that requires fewer steps for producing polymer matrix composites Reduces equipment costs: This technique eliminates the need for complex metering and mixing equipment Reduces maintenance costs: The technique reduces the heating and cleaning requirements of the injection equipment
Microvascular Networks and Composite Materials Using Sacrificial Fibers This technology is a biologically inspired 3D microvascular networks within composite materials provide damage management and active temperature regulation. ... Read More This technology is a biologically inspired 3D microvascular networks within composite materials provide damage management and active temperature regulation. Details A novel fabrication of microvascular structural material. Imagine a responsive material that has the ability to react to physical changes by delivering a functional fluid to vital, often inaccessible areas. In nature, this is accomplished through complex vasculature that transports vital fluids to tissues throughout an organism in order to regulate temperature, deliver nutrients, or begin the healing process. Scientists at the University of Illinois have taken their cue from such biological systems in fabricating a 3-dimensional vascular network within a polymer or polymer composite material that can be filled with virtually any fluid. The process is rapid, scalable and easily integrated into existing manufacturing processes with commercially available precursors. In the materials world, this system has the potential to help create longer lasting, safer and fault tolerant products. Through chemical decomposition of the sacrificial fiber relative to the matrix, the original fiber is removed from the matrix leaving behind a pervasive 3D interconnected network of microchannels that can be filled with a fluid either by using capillary action or by pumping. The choice of fluid can impart functionality to the matrix material such as self-healing, temperature regulation, or imparting visibility to areas where damage occurred through the use of a conspicuous dye. These microvascular composite materials can distribute these active fluids for reactions within the matrix in areas that are normally problematic to reach within components. The sacrificial fibers can be handled simultaneously with reinforcing fibers and decompose upon exposure to an external trigger such as processing temperature. This novel material system has the potential to restore structural integrity and extend the safety, reliability and operating life of countless components that are used everyday in numerous industry applications. For example, composite materials play an integral role in everything from aerospace and automotive applications to building materials and must maintain their integrity after repeated thermo-mechanical loading. Under such conditions, micro-cracks can develop over time within the structure significantly weakening its strength. Incorporation of a self-healing capability within the composite can instantly and permanently repair the damage, allowing the composite to retain its structural and mechanical integrity and prolonging its operational life. Figure 1: Creation of 3-D microvascular network. (A) 3-D woven preform, (B) integration of sacrifical fibers, (C) Resin infusion, (D) 3D woven composite and (E) formation of 3-D microvascular network. Applications This novel material system has the potential to restore structural integrity and extend the safety, reliability and operating life of countless components that are used everyday in numerous industry applications. Composite materials play an integral role in everything from aerospace and automotive applications to building materials and must maintain their integrity after repeated thermo-mechanical loading. Under such conditions, micro-cracks can develop over time within the structure significantly weakening its strength. Incorporation of a self-healing capability within the composite can instantly and permanently repair the damage, allowing the composite to retain its structural and mechanical integrity and prolonging its operational life. Rubber and latex industries could use this material to make improvements to existing products making them safer and longer-lasting. A self-healing tire would significantly increase safety on the road as well as reduce replacement costs. A self healing hose in air brakes for trains and trucks would significantly diminish the catastrophic risk of a failure to the brake system. Latex gloves are the primary barrier between a caregiver and possible infectious agents and tears and puncture can happen without the wearers knowledge. Using this microvascular material filled with a conspicuous dye would alert the wearer of a tear sooner. Alternatively, an anti-infective agent could be used and in the event of a tear or puncture, this agent would be released and help prevent infection. Although lithium ion batteries are gaining attention for use in automotive applications, their performance suffers at high temperatures, which are associated with quicker discharge and safety hazards. They must come with sophisticated battery management systems to maintain the proper temperatures in cars. Battery pack housing would benefit from the incorporation of a 3D microvascular material containing a temperature regulating fluid within the capillaries dissipating heat from hot spots and helping to maintain the proper thermal conditions for optimal battery life. Similarly, as computer technology moves to high-density storage and ultra-fast processing, thermal management becomes an issue. By integrating a microvascular material with a liquid capable of absorbing heat, one could create an effective and compact thermal management system for high density computational applications. Benefits Provides 3-D microvascular network for self-healing or active temperature regulation Process is scalable and can be woven into large mats All components of process are commercially available
Advanced Technique for Processing Sacrificial Fibers Researchers from the University of Illinois have developed a new method for making sacrificial fibers. This method can be used to produce larger and more complex... Read More Researchers from the University of Illinois have developed a new method for making sacrificial fibers. This method can be used to produce larger and more complex microvascular networks in polymers and fiber-reinforced composites. The better mixing method means that the networks left will be more uniform. These microvascular networks are useful for cooling, self-healing applications, or for weight saving designs.
Smart Polyurea Systems Researchers at the University of Illinois at Urbana-Champaign have developed a powerful new platform of polyureas that enable systems that are hydrolyzable, self-healing,... Read More Researchers at the University of Illinois at Urbana-Champaign have developed a powerful new platform of polyureas that enable systems that are hydrolyzable, self-healing, and malleable, opening exciting applications in the packaging, coating, and adhesives industries. In this new class of polyureas, a bulky substituent is attached to one of the nitrogen atoms of the urea bond and destabilizes the typically stable linkage leading to dynamic dissociation. The polymers can be built from the vast library of isocyanate monomers already developed for the polyurea and polyurethane industries, yielding a wide range of materials with varying, engineered characteristics. Hydrolyzable Polyureas (TF14085) Hydrolyzable polymers are currently used in the agriculture and food industries as environmentally friendly plastics and packaging materials and in the biomedical field as drug delivery systems, surgical sutures, and scaffolds for tissue engineering. However, most hydrolyzable polymers, based on polyester materials or materials containing anhydride, acetal, ketal, or imine linkages, are synthesized via condensation or ring-opening polymerizations, often requiring high temperature conditions and catalysts and resulting in by-products. In contrast, because polyureas are made via a simple and clean chemistry without catalysts or by-products, hydrolyzable polyureas offer users the ability to tune polymer systems to specific applications without involving complex chemistries. In this platform of polyureas, the destabilization introduced by the bulky substituent on the nitrogen of the urea bond leads to dynamic dissociation to the corresponding amines and isocyanates, with the isocyanates further undergoing irreversible hydrolysis in aqueous solution and complete degradation of the polyurea. Picture1.png These degradable polymers are easily synthesized by reacting multifunctional bulky amines with isocyanates and exhibit tunable degradation kinetics. Hydrolyzable Polyureas Bearing Hindered Urea Bonds Hanze Ying and Jianjun Cheng Journal of American Chemical Society 2014 136 (49), 16974-16977 Polyureas That Love to Break Down Chemical and Engineering News, December 8, 2014, http://cen.acs.org/articles/92/i49/Polyureas-Love-Break-Down.html Self-Healing Polyureas (TF12136) Incorporating the appropriate bulky substituents into polyureas enables polymers that can undergo autonomous, catalyst-free repair at room/low temperatures without the use of microcapsule healing agents, special precursors or customized laboratory/environmental conditions. Commercially available materials are used to produce self-healing polymers with capabilities to re-heal multiple times. Here the bulky substituents are chosen so that (i) the dissociation and reverse (polymer-forming) reactions are rapid and (ii) the polymer-forming reaction is highly favored, thereby insuring optimum bulk mechanical properties of the polymer. Conventional polyureas and poly(urethane-urea)s can thus readily be made dynamic and self-healing while maintaining their stability by replacing regular amines with amines containing bulky substituents. By tuning the substituent, the dynamic properties of the polymer and its mechanical properties can be controlled. Picture2.png Picture3.png Dynamic Urea Bond for the Design of Reversible and Self-Healing Polymers Hanze Ying, Yanfeng Zhang, and Jianjun Cheng Nature Communications 2014 5:3218 doi: 10.1038/ncomms4218 Also see. Malleable Polyureas (TF15006 / 2015-152) The polyurea systems can also be made malleable and recyclable by exploiting the reversible nature of the urea bond with the bulky subsituent. The cross-linked systems bearing the bulky substituents can be ground into powders and pressed/molded as shown below. Picture4.png Picture5.png The polyurea systems can also be recycled as shown below. Picture6.png
Stretchable Batteries With Self-Similar Serpentine Interconnects and Integrated Wireless Recharging Systems Researchers at the University of Illinois have developed a new design for manufacturing stretchable batteries with "self-similar serpentine interconnects" that... Read More Researchers at the University of Illinois have developed a new design for manufacturing stretchable batteries with "self-similar serpentine interconnects" that offers extraodinary stretchability along with high recharging capacity. In addition, their design also includes stretchable inductive coils that allows wireless recharging without any direct physical contact. These batteries will be useful for powering wearble and epidermal electronics, a new class of electronic and optoelectronic technology. This technology was developed in the laboratory of Dr. John Rogers, who has received international recognition for his work on bio-integrated electronics.
RMPA Compact Pattern-Reconfigurable Microstrip Parasitic Arrays This invention is a class of low-power smart antennas, operating at millimeter and microwave frequencies, which are controlled by electronically manipulating the... Read More This invention is a class of low-power smart antennas, operating at millimeter and microwave frequencies, which are controlled by electronically manipulating the direction of an antenna's signal using solid-state technology. These smart antennas are fully compatible with the existing wireless technology, as well as next generation wireless antenna arrays. Details This class of reconfigurable antennas consists of three similar antenna designs, each with its own benefits. The antenna types benefit from compact size and low power consumption, the main difference between the antennas being the geometry of the parasitic array and the method for switching microstrip polarity. How it works The three variations each have three equal spaced parallel strips printed on a grounded dielectric substrate. The center strip is driven with an SMA probe feed, and the linerally polarized antenna is matched by moving the probe location along the x-axis of the center strip. The two outer strips are parasitic and each of them contains one load in the center. When the switches are activated, or the varactors tuned, the effective electrical length of the parasitic strip changes and it alters the induced current on the parasitic strip, changing the antenna's effective radiation pattern up to +35. Applications Home/Office networking and Wi-Fi: Wireless LANs and WANs will benefit from increased range with fewer dropped connections and faster connection speeds, while users of related technologies like wireless voice over internet protocol (VoIP) would enjoy greater mobility and signal clarity. Bluetooth and other M2M systems: MIMO antenna arrays will be the backbone of countless machine-to-machine devices that rely on intercommunication in order to function. This algorithm would decrease the size of such devices while ensuring continued reliability. Handheld devices: The market demands connectivity in handheld electronics. Portable gaming devices, for instance, require access to community forums, and pocket PCs are equipped with internet browsers and multimedia software to communicate with desktop computers and wireless routers. GPS systems: A constant signal is imperative for high-accuracy GPS devices. This suite of improved antenna technologies could provide for the incorporation of GPS systems into a range of portable devices, which are currently inhibited by size, power, or portability. Cellular communications: These technologies will boost cell phone signal and range, while simultaneously minimizing power consumption and miniaturizing device size. Large or phased arrays of smart antennas: Antennas can be constructed on a large scale to improve long distance communication in cell phone broadcast towers and government/military base stations. Benefits Increase Signal to Noise Ratio: By scanning and switching the antenna's radiation pattern, the antenna system can both circumvent noise and suppress multiple path interference while maintaining communication over a single frequency. Compact size: Typically, pattern reconfigurability is achieved by using phased arrays. Phased arrays are too large for use in size-sensitive applications such as consumer electronics devices. This antenna's conformal/ planar design is ideally suited for use in these small applications. Elegant Control System: Employing a design of two or four switches, this out-of-phase antenna array consumes minimal power and has negligible computing requirements.
Method for Isolating Antennas Using Meandered-Line Ground Plane Surface Wave Filter A wireless communication device includes multiple antennas spaced apart from each other. Also included is a dielectric substrate with electrically conductive... Read More A wireless communication device includes multiple antennas spaced apart from each other. Also included is a dielectric substrate with electrically conductive ground areas along the substrate opposite the antennas. Signal coupling is decreased between the antennas by connecting the ground areas together with an isolation structure. In one nonlimiting form, this structure includes an electrically conductive meander line structure.
Series-Input Parallel Output Multiple DC-DC Converter with Dynamic Current Sharing for High-Current DC Power Supply The combination of a unique series-input parallel-output (SIPO) circuit configuration and a sensorless current mode (SCM) technique ensures automatic and nearly perfect... Read More The combination of a unique series-input parallel-output (SIPO) circuit configuration and a sensorless current mode (SCM) technique ensures automatic and nearly perfect load sharing of multiple dc:dc converters even during fast dynamic changes. A power supply in an embodiment of the invention includes a plurality of dc--dc switching power converters, each of which has its input isolated from its output. The power converters are arranged with their respective inputs being series connected and their respective outputs being parallel connected in an embodiment of the invention. In another embodiment of the inputs are parallel connected and the outputs series connected. Each power converter includes an input filter in each of said dc--dc switching power converters and an output filter. Each power converter includes a sensorless current mode control circuit controlling its switching duty ratio. To license the entire Solar Panels portfolio, click here.

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